Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare read-only, non-destructive, idempotent behavior, so the safety profile is covered. The description adds scope context (global vs. country filtering) but does not disclose return format, ordering, or pagination behavior beyond what the schema and annotations imply.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences with no filler. The first sentence front-loads the core resource and scope; the second gives practical purpose. Every word earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple, fully-optional-parameter, read-only list tool, the description plus schema and annotations covers everything needed to call it correctly. It conveys what the data is, how to scope it, and what it can be used for.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the description is not required to explain parameters. It adds little beyond the schema apart from the global/country filtering concept, which matches the 'location' parameter. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States the resource precisely: 'the most-visited domains on the internet', with explicit global or country scope. It is clear what the tool returns, but it does not explicitly distinguish itself from the sibling 'radar_domain_rank', so it lacks active sibling differentiation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides two clear use cases: seeing dominant traffic and using the list as a reference for comparing a rank. It gives clear context for when to invoke the tool, though it does not state when not to use it or point to an alternative tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.